19-55151839-T-C

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 4P and 2B. PM1 PM2 BP4_Moderate

The NM_000363.5(TNNI3):c.628A>G(p.Ser210Gly) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 13/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. S210N) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: TNNI3 NM_000363.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.265

Genes affected

TNNI3 (HGNC:11947): (troponin I3, cardiac type) Troponin I (TnI), along with troponin T (TnT) and troponin C (TnC), is one of 3 subunits that form the troponin complex of the thin filaments of striated muscle. TnI is the inhibitory subunit; blocking actin-myosin interactions and thereby mediating striated muscle relaxation. The TnI subfamily contains three genes: TnI-skeletal-fast-twitch, TnI-skeletal-slow-twitch, and TnI-cardiac. This gene encodes the TnI-cardiac protein and is exclusively expressed in cardiac muscle tissues. Mutations in this gene cause familial hypertrophic cardiomyopathy type 7 (CMH7) and familial restrictive cardiomyopathy (RCM). Troponin I is useful in making a diagnosis of heart failure, and of ischemic heart disease. An elevated level of troponin is also now used as indicator of acute myocardial injury in patients hospitalized with moderate/severe Coronavirus Disease 2019 (COVID-19). Such elevation has also been associated with higher risk of mortality in cardiovascular disease patients hospitalized due to COVID-19. [provided by RefSeq, Aug 2020]

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 7 uncertain in NM_000363.5
• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.08936459).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TNNI3	NM_000363.5	c.628A>G	p.Ser210Gly	missense_variant	8/8	ENST00000344887.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TNNI3	ENST00000344887.10	c.628A>G	p.Ser210Gly	missense_variant	8/8	1	NM_000363.5	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Hypertrophic cardiomyopathy Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Apr 26, 2023

In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Not Available"; PolyPhen-2: "Benign"; Align-GVGD: "Not Available". The glycine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. This variant has not been reported in the literature in individuals affected with TNNI3-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces serine, which is neutral and polar, with glycine, which is neutral and non-polar, at codon 210 of the TNNI3 protein (p.Ser210Gly). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.21
CardioboostCm	Benign	0.0088
BayesDel_addAF	Uncertain	0.096	D
BayesDel_noAF	Benign	-0.10
Cadd	Benign	19
Dann	Uncertain	0.99
DEOGEN2	Uncertain	0.43	T;T
Eigen	Benign	-0.76
Eigen_PC	Benign	-0.57
FATHMM_MKL	Benign	0.11	N
LIST_S2	Uncertain	0.92	D;D
M_CAP	Benign	0.052	D
MetaRNN	Benign	0.089	T;T
MetaSVM	Uncertain	-0.25	T
MutationAssessor	Benign	0.55	N;.
MutationTaster	Benign	1.0	N;N
PrimateAI	Uncertain	0.50	T
PROVEAN	Benign	-0.77	N;.
REVEL	Uncertain	0.35
Sift	Benign	0.44	T;.
Sift4G	Uncertain	0.012	D;D
Polyphen		0.0	B;.
Vest4		0.062
MutPred		0.28		Loss of phosphorylation at S210 (P = 0.0042);.;
MVP		0.74
MPC		0.60
ClinPred		0.091	T
GERP RS		3.6
Varity_R		0.13

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs1599907495; hg19: chr19-55663207;